How does an animal determine what behavior to express in the face of conflicting information from its environment? For example, activation of campaniform sensilla on the male cerci provides important feedback information to the motor program responsible for spermatophore threading and transfer in the cricket, Acheta domesticus. However, activation of these same sensory inputs in non- mating males triggers defensive kicking of the metathoracic legs. What neural mechanisms allow these sensory neurons to play such an important role in two mutually incompatible behaviors--mating and escape? One possibility is that descending inputs from the brain may suppress the kick circuit during mating. A second possibility is that neurohormones or modulators released within the central nervous system of male crickets are responsible for this behavioral switch' from kicking to mating. The long-term goal of the proposed studies is to use a relatively simple animal preparation to investigate the specific mechanisms involved in sensorimotor integration at the cellular, systems and behavioral level. Experiments are designed to characterize the central neural elements that generate the rhythmic motor activity that underlies male spermatophore threading behavior, and the effects of both central and peripheral feedback in reinforcing or reconfiguring this rhythmic motor activity. By studying this model system, where the various components involved in producing a relatively simple behavioral response can be identified and assessed, significant insight can be gained into the mechanisms by which the nervous system transforms complex sensory information into an appropriate behavioral response.